Fair Value (Unobservable Input Reconciliation) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Residential mortgage loans - FVO
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	$ 175	$ 262	$ 188	$ 299
Total realized/unrealized gains (losses) included in net income (loss)	6	2	10	8
Total realized/unrealized gains (losses) included in AOCI	0	0	0	0
Purchases	0	0	0	0
Sales	0	(39)	(7)	(64)
Issuances	0	0	0	0
Settlements	(5)	(7)	(15)	(25)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance, end of period	176	218	176	218
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	6	(8)	6	(7)
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	0		0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	6	(8)	6	(7)
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	0		0
Net Derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	1	28	52	36
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	(28)		801
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance, beginning of period	938	73	(72)	(192)
Total realized/unrealized gains (losses) included in net income (loss)	5	81	236	51
Total realized/unrealized gains (losses) included in AOCI	(20)	215	993	439
Purchases	0	0	0	4
Sales	0	0	0	0
Issuances	0	0	0	(1)
Settlements	(132)	(115)	(366)	(47)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance, end of period	791	254	791	254
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	1	28	52	36
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	(28)		801
Net Embedded Derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	266	(423)	(894)	(843)
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	0		0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance, beginning of period	(2,571)	(1,219)	(1,325)	(704)
Total realized/unrealized gains (losses) included in net income (loss)	270	(424)	(889)	(847)
Total realized/unrealized gains (losses) included in AOCI	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(47)	(52)	(134)	(144)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance, end of period	(2,348)	(1,695)	(2,348)	(1,695)
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	266	(423)	(894)	(843)
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	0		0
Corporate fixed maturity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	12,978	7,650	9,382	7,101
Total realized/unrealized gains (losses) included in net income (loss)	(3)	(11)	(85)	(13)
Total realized/unrealized gains (losses) included in AOCI	409	79	157	439
Purchases	705	732	2,307	1,495
Sales	(485)	(203)	(823)	(483)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	512	527	3,339	484
Transfers out of Level 3	(236)	(58)	(397)	(307)
Balance, end of period	13,880	8,716	13,880	8,716
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(5)	(4)	(48)	(8)
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	401		135
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(5)	(4)	(48)	(8)
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	401		135
Structured Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	4,546	3,242	3,395	3,541
Total realized/unrealized gains (losses) included in net income (loss)	23	10	29	34
Total realized/unrealized gains (losses) included in AOCI	80	0	(18)	41
Purchases	263	425	1,555	597
Sales	(282)	(116)	(570)	(408)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	26	0	57	1
Transfers out of Level 3	(324)	(104)	(116)	(349)
Balance, end of period	4,332	3,457	4,332	3,457
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	13	10	34	33
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	80		(18)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	13	10	34	33
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	80		(18)
Foreign government
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	15	10	10	10
Total realized/unrealized gains (losses) included in net income (loss)	0	0	0	0
Total realized/unrealized gains (losses) included in AOCI	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	(1)	(1)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	1
Transfers out of Level 3	(8)	0	(2)	0
Balance, end of period	7	10	7	10
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	0		0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	0		0
Municipals
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	0	7	7	0
Total realized/unrealized gains (losses) included in net income (loss)	0	0	0	0
Total realized/unrealized gains (losses) included in AOCI	1	0	1	0
Purchases	2	0	2	7
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	(7)	0
Balance, end of period	3	7	3	7
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	1		1
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	1		1
Short-term Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	0	113	17	25
Total realized/unrealized gains (losses) included in net income (loss)	0	1	0	1
Total realized/unrealized gains (losses) included in AOCI	0	0	0	(1)
Purchases	0	251	0	363
Sales	0	(2)	(2)	(25)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	(15)	0
Balance, end of period	0	363	0	363
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	1	0	1
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	0		0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	1	0	1
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	0		0
Other Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	696	620	799	571
Total realized/unrealized gains (losses) included in net income (loss)	14	5	18	63
Total realized/unrealized gains (losses) included in AOCI	0	0	0	0
Purchases	0	51	31	80
Sales	(60)	(22)	(97)	(60)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	(128)	0	(229)	0
Balance, end of period	522	654	522	654
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	13	6	20	55
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	0		0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	13	6	20	55
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	0		0
Separate Accounts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	912	925	915	937
Total realized/unrealized gains (losses) included in net income (loss)	0	5	1	10
Total realized/unrealized gains (losses) included in AOCI	0	0	0	0
Purchases	72	89	119	129
Sales	(26)	(88)	(90)	(146)
Issuances	(2)	0	(4)	2
Settlements	0	(2)	1	(3)
Transfers into Level 3	0	0	10	0
Transfers out of Level 3	(9)	0	(5)	0
Balance, end of period	947	929	947	929
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	0		0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	$ 0	0	$ 0
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	$ 0		$ 0